Study of T-wave End Detection with Geometric Method / 中国医学物理学杂志

Purpose: To realize the detection of T-wave end with an efficient and accurate method. Methods: R-wave was lo-cated using wavelet transforming, and then the T-wave detection interval was identified accttrately by avoiding the influence of heart rate and P-wave. In addition, T-wave peaks were determined referring to the modulus maxima in the interval. Based on these, the T-wave end was located with a simple and practical geometrical method, which was applied for the evaluation of QT database. Results: The positioning capability of the above-mentioned method reached to (-0.35225±18.5869) ms which was comparable or even better than those manual annotations from QT database by cardiologists. Conclusions: The experimental results showed that our algorithm for T-wave end detection is robust to noise, baseline drift and waveform morphological varia-tions, and easy to calculate and to realize.

Study of hybrid time-frequency method and characterization of atrial fibrillation from surface ECG / 生物医学工程学杂志

With the non-invasive analysis of time-frequency features and instantaneous frequency (IFs) of atrial fibrillation (AF) from surface ECG signals, some important information reflecting the dynamic behavior of atria with AF can be extracted. In this paper is proposed a hybrid time-frequency analysis method, which uses the respective advantages of Gabor expansion and quadratic Wigner distribution. Our study showed that the time-frequency representation of atrial fibrillation signals was formulated into the combinations of time-frequency atoms series. By controlling the trade-off of resolution and interference terms via Manhattan distance threshold, this method in combination with moment-based computation obtained more robust estimation of IFs. The comparative analysis of 10 pairs of non-terminating and terminating types of AF signals suggested that hybrid estimation of IFs can detect the reduction of a majority of the fibrillatory rate when AF will end. Meanwhile, this method decreases compute burden and is a more robust way relative to peak-based or spectrogram method. So, the proposed method would have prospective applications in clinical management of atrial fibrillation.

Advances in the computer-based atuo-analysis of atrial fibrillation electrophysiology / 国际生物医学工程杂志

This article mainly introduces the new development of signal processing techniques used in analyzing electrophysiological signals of atrial fibrillation. Discussions and suggestions are given differently in the view of start, methods and values of clinical applications. The introduction is hoped to give some guidance to the domestic research in the correspondent fields.